1. Field of the Invention
The invention relates to a process for preparing substituted 2-pyrimidinecarboxylates by reacting 2-halopyrimidines with carbon monoxide and an alcohol in the presence of a catalyst and a base. The esters which can be prepared according to the invention have the general formula: ##STR2## wherein: R is C.sub.1-6 -alkyl, C.sub.3-6 -cycloalkyl, aryl or arylalkyl, and
R.sup.1 to R.sup.3 are, independently of one another, hydrogen, C.sub.1-6 -alkyl, fluorinated C.sub.1-6 -alkyl, C.sub.1-6 -alkoxy, (C.sub.1-6 -alkoxy)-C.sub.1-6 -alkyl or (C.sub.1-6 -alkoxy)carbonyl.
2. Background Art
Compounds having the structure of formula I are intermediates for the preparation of herbicides (European Published Patent Application No. 0152286 and German Published Patent Document No. 3,836,230) or pharmaceutically active ingredients (German Published Patent Document No. 2,341,925). Known syntheses of these compounds proceed, for example, from the corresponding 2-methylpyrimidines, whose methyl group is oxidized to form the carboxyl group with potassium permanganate and is then esterified see, for example, H. Neunhoeffer and G. Werner, Liebigs Ann. Chem., (1974), 1190-1194!. The synthesis of the compounds in which R.sup.1 .dbd.R.sup.3 =alkoxy normally proceeds from the propanediimidates obtainable from malonic dinitrile and alcohols and the monoxalate chlorides H. Eilingsfeld et al., Chem. Ber., (1968), 101, 2426-2434!.